When applying a flowable substance to an article or substrate, it is required that, with identical substrate quality and identical substance quality, or in the case of coloring, with the same color concentration, the result of the application always be the same. This means that one always must be certain to apply exactly the same quantity of substance in the same manner (superficially or in-depth), from the first to the last produced meter of the substrate coated. It is also desirable to reach this goal at any production speed so that all textile finishing processes can be effected with variable speed but constant quality results. The printer, dyer, application operator, or finisher at the machine should not have to be the one to empirically adjust the production quality and be reponsible therefor. He should define and adjust the optimal speed from the technical point of view of the process and optimize the general process flow of all steps such as printing, steaming, washing, drying and the like. It is also to be considered that with today's production speed and working widths, which can reach 5 m and more, the operator of the machine is hardly capable of intervening quickly to control such a process, so that the danger of producing massive amounts of rejects is present.